1. Field of the Invention
This invention relates to a keyboard assembly, and more particularly to a keyboard assembly which is improved in the facility of assemblage thereof.
2. Prior Art
Conventionally, a keyboard assembly used in musical instruments operated by using a keyboard, such as an electronic piano, is assembled by separately fabricating keys and a key support member such as a key frame, and then mounting the keys on the key support member. In general, the key support member of the keyboard assembly has key depression-detecting means, such as key switches, mounted thereon for detecting depression of the respective keys. The key depression-detecting means have resilient expanded portions made e.g. of rubber. Each key has an actuator formed thereon for depressing a corresponding one of the resilient expanded portions when it is depressed or operated by the player, and when the depression of the key is detected by the key depression-detecting means, a key-on signal is generated.
To ensure proper functioning of the key depression-detecting means, each key is required to be mounted at a location at which the actuator of the key is properly brought into abutment with the resilient expanded portion. To this end, a conventional keyboard assembly has been proposed by Japanese Laid-Open Patent Publication (Kokai) No. 6-110450, which includes a guide member provided on the bottom of a common rear end portion of each key, which serves not only as positioning means but also as guiding means for guiding the key when it is mounted, and a hole corresponding to the guide member, which is formed in a key support member. The guide member is inserted into the hole for positioning the key, and then the common rear end portion of the key is fixed to the key support member by a screw or the like.
Another conventional keyboard assembly proposed by the above-mentioned Japanese Laid-Open Patent Publication (Kokai) No. 6-318076 includes a single dowel pin provided on each key unit in a fashion protruding from the bottom of a common rear end portion of keys, a hole formed in a key support member for receiving the dowel pin, and a projection formed on the key support member, for abutment with a rear end of the common rear end portion of the keys. The dowel pin holds the key unit at one contact point, and the projection prevents the key unit from undergoing a slight horizontal pivotal motion about the dowel pin, to thereby hold the key unit (and hence keys) in position. Further, finally, the common rear end portion of the keys is fixed to the key support member by screws.
Normally, the key depression-detecting means, the key support member, and the keys are fabricated separately. Therefore, improper contact or abutment of each actuator on the corresponding resilient expanded portion can be caused not only by manufacturing tolerances of the component parts but also by positioning or alignment errors therebetween (mounting errors). Further, when a plurality of key units are mounted on the body of the keyboard assembly, one key unit can suffer from similar inconveniences ascribable to tolerances or mounting errors of component parts of another key unit.
Even if there are such tolerances or mounting errors, so long as the bottom of each actuator is flat in shape and has a sufficient longitudinal length, an error in the longitudinal position of the key can be accommodated to some extent whereby it is possible to bring the actuator into contact with the resilient expanded portion to a proper extent. However, an error in the lateral position of each key can be accommodated only to a very slight extent due to a limited width thereof. If such an error cannot be accommodated or compensated for, the key (or key unit) is regarded as defective, and the mounting of a key (or key unit) has to be carried out again, resulting in not only degraded productivity but also a lowered yield of keys, which leads to an increase in the manufacturing cost.
FIG. 1 shows an outline of the construction of a conventional keyboard assembly, which is in a pre-assembled state.
In the conventional keyboard assembly, keys are preassembled into key units 91, each formed as a laminate of white keys and black keys, and mounted on a key support member 92. The mechanism of the keyboard assembly imposes various requirements on the manner of mounting the key units 91 on the key support member 92.
First, a key switch 93 as key depression-detecting means operates to detect depression of a key corresponding thereto by sensing an urging force of the key acting thereon. Therefore, after the key unit 91 has been mounted on the key support member 92, when a key is in a released state, normally, an actuator 94 formed on the key lightly contacts the resilient expanded portion of the key switch 93. On the other hand, during the mounting process of the key unit 91 on the key support member 92, to prevent the actuator 94 from applying a horizontal external force to the resilient expanded portion, which leads to peeling and deformation of the resilient expanded portion, it is desirable that the actuator 94 abuts or urges the resilient expanded portion vertically or from right above. Although peeling and deformation of the resilient expanded portion can be prevented by increasing the hardness thereof, this degrades a key touch sensed when the key is depressed. Therefore, the actuator 94 and the resilient expanded portion are required to be kept out of contact from each other up to a stage immediately before the mounting process of the key unit 91 is finished when the key unit is no longer moved horizontally.
For example, in the conventional keyboard assembly, each key 91 has a guide projection 96 formed on the bottom of a rear end portion (common rear end portion 95) thereof, and at the same time, the key support member 92 has a hole 97 formed therein for having the guide projection 96 fitted therein when the key unit 91 has been mounted, whereby the rear half of each key is supported by the guide projection 96 up to a stage immediately before the mounting of the key unit 91 is completed. Further, during the mounting process of the key unit 91, the front half of each key is supported by the top of a key guide 98 (provided for preventing a transverse sway or twist of the key when it is depressed). Other examples are disclosed in Japanese Laid-Open Patent Publications (Kokai) Nos. 6-318076 and 8-123419, in which a guide member for supporting the rear half of each key is provided not on the key unit 91 but on the key support member 92 for the ease of handling of the key before mounting of the key unit.
Further, a plurality of guide members for assisting the mounting operation of the key unit 91, such as the guide projection 96, are normally provided. However, these members should not interfere with key depressing operations by the operator or player. In the conventional keyboard assembly, after the key unit 91 has been mounted, the guide projection 96 are fitted in the holes 97 to thereby prevent the guide projection from interfering with key-depressing operations by the user.
Further, it is necessary to provide a so-called upper limit stopper for setting an upper limit position of a front end (operator side-end) of each key when the key is a released state after the mounting of the key unit 91. For example, in the conventional keyboard assembly, each key is integrally formed with a follower portion 99 which is slidably guided by the key guide 98, and the follower portion 99 has an engaging end 99a formed integrally at a lower end thereof for abutting on a stopper, not shown, provided at a location close to a lower end of the key guide 98 when the depressed key returns to its original released position.
Furthermore, to facilitate accurate mounting operations of keys, means for controlling the position of each key in a lateral direction, i.e. in a direction in which keys are juxtaposed is indispensable. In the conventional keyboard assembly, for example, the position of each key in the lateral direction is controlled by lateral opposite sides of the key guide 98 which controls the lateral position of the follower portion 99 of the key.
During the mounting process of the key unit 91, the key unit 91 is slid rearward, and then moved downward. According to the above construction of the conventional key board assembly, as the key unit 91 is slid rearward, the engaging end 99a is horizontally moved rearward below the key guide 98, and, immediately before termination of the mounting of the key unit 91, the actuator 94 abuts the resilient expanded portion of the key switch 93 from right above. This enables the key unit 91 to be properly mounted on the key support member 92 while avoiding peeling and deformation of the resilient expanded members and other inconveniences.
However, in the conventional keyboard assembly, the key guide 98 (top end thereof) of the key support member for supporting the front end of each key is closer to a central portion of the key rather than the rear end portion of the same, so that the support of the key by the key guide is not stable enough to easily carry out a mounting operation of the key unit 1 on the key support member.
Further, the key guide 98 is provided for each of the keys. Therefore, it is required to set the top of each key guide 98 to a suitable height, which complicates the construction of the keyboard assembly, and increases the manufacturing cost.
Further, the guide member for supporting the rear end portion of each key, such as the guide projection 96, does not play any role after the mounting of each key (key unit) is completed, and provision of such guide members undesirably narrows the mounting space for accommodating other component parts of the keyboard assembly.
It is a first object of the invention to provide a keyboard assembly which is capable of lessening the required accuracy of mounting of each key to thereby improve the productivity and reduce the manufacturing cost.
It is a second object of the invention to provide a keyboard assembly which is simple in construction and low in manufacturing cost but enables keys to be more easily mounted on a key support member to thereby improve the ease of assemblage of the keyboard assembly.
It is a third object of the invention to provide a keyboard assembly which is simple in construction and low in manufacturing cost but is capable of saving the mounting space while maintaining the ease of handling keys before or during mounting of them, and further capable of preventing degradation of a key touch sensed when each key is depressed as well as peeling and deformation of each resilient expanded portion.
To attain the first object of the invention, according to a first aspect of the invention, there is provided a keyboard assembly comprising a plurality of keys, each of the keys including a body, a hinge portion, and a rear end portion, a key support member for pivotally supporting the keys, and movably-mounting means for mounting the keys onto the key support member via the rear end portion of the each of the keys in a manner such that the keys can be moved by moving the rear end portion of the each of the keys, and wherein when said keys have been mounted on said key support member, said movably-mounting means engages said keys with said key support member in a manner such that said keys are movable relative to said key support member.
Preferably, the movably-mounting means mounts the keys onto the key support member via the rear end portion of the each of the keys in a manner such that the keys can be moved in a direction in which the keys are juxtaposed by moving the rear end portion of the each of the keys.
Preferably, the movably-mounting means includes vertical position-limiting means for limiting a vertical position of the keys, and a longitudinal position-liming means for limiting a longitudinal position of the keys, the longitudinal position-limiting means including a reference surface formed on the key support member and extending in a direction in which the keys are juxtaposed, for determining a reference position for the longitudinal position of the keys, and an abutment surface formed on the keys, for abutting the reference surface when the keys are mounted on the key support member.
More preferably, the longitudinal position-limiting means includes urging means for bringing the abutment surface into slidable urging contact with the reference surface.
Preferably, the keyboard assembly includes guide means for guiding the keys into a position where the keys are mounted onto the key support member.
Preferably, the keys are preassembled into at least one key unit before being mounted on the key support member, the at least one key unit each having a common rear end portion including the rear end portion of the each of the keys, the abutment surface being formed on the common rear end portion.
More preferably, the key support member has a rear end portion having an upper surface, the urging means including protrusion means formed on the upper surface of the rear end portion of the key support member and extending in a direction in which the keys are juxtaposed, the protrusion means having the reference surface, at least one resilient piece formed on the common rear end portion of the at least one key unit in a fashion projecting downward, and at least one through hole formed through the rear end portion of the key support member at a location corresponding to the at least one resilient piece, the at least one resilient piece being inserted through the at least one through hole.
Further preferably, the rear end portion of the key support member has a lower surface, the at least one resilient piece each having a hook formed at a lower end thereof in a fashion projecting rearward, for engagement with the lower surface of the rear end portion of the key support member.
Further preferably, the protrusion means comprises a front protrusion and a rear protrusion formed at a front location and a rear location of the upper surface of the rear end portion of the key support member, respectively, the front protrusion having a rear surface and the rear protrusion having a front surface, the reference surface being formed by the rear surface of the front protrusion, the common rear end portion being fitted between the rear surface of the front protrusion and the front surface of the rear protrusion.
Even more preferably, the common rear end portion has a front lower end and a rear lower end, the guide means comprising a front guide member and a rear guide member formed respectively in line with the front protrusion and the rear protrusion, the front guide member and the rear guide member having inclined upper portions on respective sides thereof opposed to each other, for abutment with the front lower end and the rear lower end of the of the common rear end portion when the at least one key unit is mounted on the key support member.
Still more preferably, the front guide member has a rear lower edge flush with the reference surface of the front protrusion, and the rear guide member has a front lower edge portion flush with the front surface of the rear protrusion.
To attain the second and third objects, according to a second aspect of the invention, there is provided a keyboard assembly comprising a plurality of keys, a key support member for pivotally supporting the keys, the key support member having a main body, a plurality of key depression-detecting means each arranged on the key support member, for detecting a depression of a corresponding one of the keys, each of the key depression-detecting means having a resilient expanded portion, an actuator formed on each of the keys, for depressing the resilient expanded portion of a corresponding one of the key depression-detecting means, a keyslip provided on the main body of the key support member, and a ridge formed on the keyslip and extending in a direction in which the keys are juxtaposed, for slidably supporting the keys when the keys are mounted onto the key support member.
Preferably, the keys are preassembled into key units, each formed of a laminate of white keys and black keys, before being mounted onto the key support member.
To attain the second and third aspects, according to a third aspect of the invention, there is provided a keyboard assembly comprising a plurality of keys, a key support member for pivotally supporting the keys, a plurality of key depression-detecting means each arranged on the key support member, for detecting a depression of a corresponding one of the keys, each of the key depression-detecting means having a resilient expanded portion, an actuator formed on each of said keys, for depressing the resilient expanded portion of a corresponding one of the key depression-detecting means, at least one first guide rib formed on the key support member at a location opposed to a corresponding portion of at least one of the keys, for guiding the at least one of the keys when the keys are slid rearward to be mounted onto the key support member, and a recess formed in each of the corresponding portion of the at least one of the keys, for receiving a corresponding one of the at least one first guide rib after completion of mounting of the keys onto the key support member.
Preferably, the keyboard assembly includes at least one second guide rib formed on the key support member at a location opposed to a corresponding second portion of the at least one of the keys, for limiting a position of the each of the keys in a direction in which the keys are juxtaposed to a range within which the first guide rib can be received into the recess when the keys are slid rearward.
Preferably, the keys are preassembled into at least one key unit, each formed of a laminate of white keys and black keys, before being mounted onto the key support member, the recess being formed in each of the black keys.
Preferably, the keyboard assembly includes a ridge formed on the key slip and extending in a direction in which the keys are juxtaposed, for slidably supporting the keys when the keys are mounted onto the key support member.
To attain the first to third objects of the invention, according to a fourth aspect of the invention, there in provided a keyboard assembly comprising a plurality of keys, each of the keys including a body, a hinge portion, and a rear end portion, a key support member for pivotally supporting the keys, the key support member having a main body, a plurality of key depression-detecting means each arranged on the key support member, for detecting a depression of a corresponding one of the keys, each of the key depression-detecting means having a resilient expanded portion, an actuator formed on each of the keys, for depressing the resilient expanded portion of a corresponding one of the key depression-detecting means, a keyslip provided on the main body of the key support member, a ridge formed on the keyslip and extending in a direction in which the keys are juxtaposed, for slidably supporting the keys when the keys are mounted onto the key support member via the rear end portion of the each of the keys, and movably-mounting means for mounting the keys onto the key support member in a manner such that the keys can be moved by moving the rear end portion of the each of the keys, wherein when the keys are mounted onto the key support member, the keys are moved into a predetermined position by sliding the keys on the ridge, to be mounted onto the key support member, and when the keys have been mounted on the key support member, the movably-mounting means engages the keys with the key support member in a manner such that the keys are movable relative to the key support member.
To attain the first to third objects of the invention, according to a fifth aspect of the invention, there is provided a keyboard assembly comprising, a plurality of keys, a key support member for pivotally supporting the keys, a plurality of key depression-detecting means each arranged on the key support member, for detecting a depression of a corresponding one of the keys, each of the key depression-detecting means having a resilient expanded portion, an actuator formed on each of the keys, for depressing the resilient expanded portion of a corresponding one of the key depression-detecting means, at least one guide rib formed on the key support member at a location opposed to a corresponding portion of at least one of the keys, for guiding the at least one of the keys when the keys are slid rearward to be mounted onto the key support member, a recess formed in the corresponding portion of the at least one of the keys, for receiving a corresponding one of the at least one guide rib after completion of mounting of the keys onto the key support member, and movably-mounting means for mounting the keys onto the key support member in a manner such that the keys can be moved by moving the rear end portion of the each of the keys, wherein the movably-mounting means cooperates with the recess to engage the keys with the key support member in a manner such that the keys are movable relative to the key support member when the keys have been mounted on the key support member.
To attain the first to third objects of the invention, according to a sixth aspect of the invention, there is provided a method of assembling a keyboard assembly including a plurality of keys, each having a free front end portion having a lower surface, and a rear end portion, a key support member for pivotally supporting the keys, the key support member having a main body, a keyslip provided on the main body of the key support member, a ridge formed on the keyslip and extending in a direction in which the keys are juxtaposed, at least one guide rib formed on the key support member at a location opposed to a corresponding portion of at least one of the keys, a recess formed in the corresponding portion of the at least one of the keys, and movably-mounting means having vertical position-limiting means for limiting a vertical position of the keys, and a longitudinal position-limiting means for limiting a longitudinal position of the keys, the movably-mounting means permitting movement of the keys in the direction in which the keys are juxtaposed, within a limited range relative to the key support member, the method comprising a first step of placing the lower surface of the free front end portion of each of the keys in contact with the ridge, a second step of moving the keys relative to the key support member in a manner such that the guide rib is fitted into the recess, while allowing the lower surface of the free front end portion of the each of the keys to slide on the ridge, and a third step of mounting the keys onto the key support member via the rear end portion of the each of the keys in a manner such that the keys can be moved by moving the rear end portion of the each of the keys.
Preferably, the movably-mounting means includes at least one projection formed on one of at least one of the rear end portions of the keys and a corresponding portion of the key support member, and at least one hole formed in the other of the at least one of the rear end portions of the keys and the corresponding portion of the key support member at a location corresponding to the at least one hole, the at least one hole having such a size relative to a size of the at least one projection as permits movement of the keys in the direction in which the keys are juxtaposed, within the limited range relative to the key support member.
Further preferably, the movably-mounting means includes engaging means formed on the at least one projection for engagement with the at least one hole when the at least one projection is inserted through the at least one hole, the method including a fourth step of adjusting a position of the keys in the direction in which the keys are juxtaposed when the keys are mounted on the key support member while the engaging means engages with the at least one hole.
The above and other objects of the invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings.